In many manufacturing environments, performing relative alignment of parts of components usually require labor intensive alignment system setup, and a direct line-of-sight between master and slave components (if optical alignment tools are used). The methods typically also require training of the personnel performing the alignment tasks and large amount of time for setting up equipment.
Currently, alignments are performed on aircraft and spacecraft manufacturing floors using either optical (laser) alignment tools that are usually large in-size and cannot be used in hard-to-reach locations. These methods are expensive and time consuming and not consistent with lean-manufacturing process.
Inertial sensors, including, for example, accelerometers and gyroscopes, commonly are used to determine direction of a moving platform based upon the sensed inertial reaction of an internally moving proof mass. For example, a typical electromechanical gyroscope comprises a suspended proof mass, gyroscope case, pickoffs, forcers and readout electronics. The inertial proof mass is internally suspended from the gyroscope case that is rigidly mounted to the platform and communicates the inertial motion of the platform while otherwise isolating the proof mass from external disturbances. The pickoffs that sense the internal motion of the proof mass, the forcers that maintain or adjust this motion and the readout electronics that must be in close proximity to the proof mass are internally mounted to the case, which also provides the electrical feedthrough connections to the platform electronics and power supply. The case also provides a standard mechanical interface to attach and align the gyroscope with a moving platform. In various forms, gyroscopes often are employed as a critical sensor for vehicles such as aircraft and spacecraft. They are generally useful for navigation or whenever it is necessary to autonomously determine the orientation of a free object.
Inertial tools are used infrequently in alignment applications. This is probably because most inertial tools are either too large or too expensive. Accuracy also is a common issue with most inertial tools.